Warning: This recap for “The Doctor Falls” episode of Doctor Who contains spoilers.

And so Peter Capaldi’s three-season tenure as The Doctor ended with him coming face to face with…Walder Frey? Yes, that was Game of Thronesstar David Bradley, whom Whovians glimpsed in the closing moments of tonight’s Season 10 finale, “The Doctor Falls.” But no, the British character actor wasn’t portraying the dreaded orchestrator of the Red Wedding, last seen bleeding out after Arya Stark sliced his throat. Instead, Bradley dusted off his William Hartnell impression from the 2013 Doctor Who docudrama, An Adventure of Space and Time, which celebrated the show’s 50-year legacy by recreating its early years, from the pilot to Hartnell’s regeneration.

In “The Doctor Falls,” though, Bradley isn’t merely playing the actor who playedthe First Doctor — he’s actually playing the First Doctor, who emerges here from a snowy landscape to encounter his Twelfth counterpart. Capaldi’s Doctor is in the midst of actively fighting the regeneration process that was initiated during his final fight with the Cybermen aboard the Mondas-originated colony ship. Having fallen on the battlefield, his prone body was carried to the TARDIS by former companion-turned-Cyberman-turned-living fluid (more on that in a bit), Bill Potts (Pearl Mackie). Jolted awake by regeneration energy, the Doctor starts repeating the past words of some of his predecessors, including Four (“Sontarans perverting the course of human history!”), Ten (“I don’t want to go”), and Eleven (“When the Doctor was me”).

But Twelve then makes it clear that he’s not going anywhere without a fight. “I don’t want to change again, never again!” he yells into the empty TARDIS. “I can’t keep on being somebody else.” He then makes straight for the doors and is greeted with a blast of Arctic wind and snow. Plunging his glowing hands into the snow, he wards off regeneration again, crying out “I will not change!” Those words are then repeated back to him by the passing figure of the First Doctor, who takes issue with Twelve introducing himself as “The Doctor.” “You may be a Doctor,” his past self remarks, “But I am the Doctor. The original you might say.” (If those words sound familiar, Capaldi uttered them earlier in the finale, just before attacking the Cybermen.)

You’ll have to wait until the annual Christmas episode in December to see how these Doctors settle their differences, and who ultimately replaces the outgoing Capaldi as lucky number Thirteen. But showrunner Steven Moffat — who is following his leading man out of the TARDIS — is setting up a conclusion that, in a sense, brings the entire franchise full circle. Let’s just say it’s no accident that the two Doctors are encountering each other in the snow: after all, that’s where Hartnell spent his final adventure as the First Doctor began in the four-part serial, “The Tenth Planet.” Those episodes also mark the introduction of the Cybermen, who invade the Snowcap base located at Earth’s South Pole, forcing the Doctor and his two companions into action. The fourth chapter features the franchise’s first-ever regeneration, with Hartnell’s face replaced by Patrick Troughton. (That full episode is among the many missing chapters of Doctor Who, although the regeneration scene miraculously survived.)

So it appears that Nos. 1 and 12 are meeting in the South Pole on the verge of their respective regenerations. Perhaps they’ll also set aside some time to visit their mutual granddaughter (and very first companion), Susan Foreman, whose picture was glimpsed in the Season 10 premiere. It’s worth nothing that at the time of “The Tenth Planet,” Susan had settled down to live on a future Earth, and Capaldi has previously said that he’s hoping for a grandfather/granddaughter reunion before his tenure ends. And, in the past, Moffat has given his leading man what he wants: in 2015, Capaldi put it out there that he was eager to tangle with some Mondasian Cybermen, which is precisely what happens in this finale. One more thing to keep in mind: Moffat might use the Christmas episode to pinpoint where exactly the Twelfth Doctor was during the all-star 50th anniversary special, Day of the Doctor, which aired in November 2013, after Capaldi’s casting was announced, but before Eleven officially regenerated. (Capaldi’s eyes appeared in a montage united all the Doctors, past, present and future.) If it happens, that may close a time loop that will give incoming showrunner, Chris Chibnall, a whole new galaxy to play with when he takes over Doctor Who for its 11th season, and Thirteenth Doctor.

We’re tearing up just thinking about saying goodbye to Capaldi six months from now, which will be the longest fans have ever had to wait from the beginning of a regeneration to the end. But the Christmas special is going to have to work extra hard to top the many tearjerking moments featured in “The Doctor Falls.” Here are the finale’s Top 5 cry points.

Bill Realizes She’s a CybermanWhile everyone else can see that Bill has been in the Cybermen’s image, she still believes she’s human. That is, until she gazes upon her true reflection in a mirror offered to her by one of the young residents of Level 507. It’s a moment straight out of Frankenstein,as she’s forced to gaze upon the creature she’s become. And, deep down, she knows there’s no going back. “People are always going to be afraid of me, aren’t they?” the gentle soul tells the Doctor, before adding, “I don’t want to live if I can’t be me anymore.” Adding to the sadness of this scene is the memory of just how happy Bill was when she first started hopping through time and space as the Doctor’s latest companion.

The Doctor Pleads with MissyThe Doctor and the Master have been locked in opposition since time immemorial. But in the Master’s new form as Missy, Twelve sees a chance to finally break that cycle. So it’s she that he appeals to — rather than her previous incarnation (John Simms) — on the eve of his desperate last stand against the Cybermen. “Stand with me. It’s all I’ve ever wanted,” he says, naked sorrow in his voice. “Me too,” she tearfully replies, nevertheless moving on and leaving him behind. That turns out to be their final encounter; although she plans to return to the Doctor’s side, she’s literally stabbed in the back by the earlier version of herself, which makes for an appropriately tragic twist of fate.

Nardole Shows His StrengthLike Lin-Manuel Miranda wrote, “Dying is easy, young man. Living is harder.” Vowing to stay and fight alongside the Doctor, Nardole is ultimately persuaded by the Time Lord’s gracefully-phrased challenge: “One of us has to stay here and blow up a lot of silly tin men, and one of us has to go up there and look after a lot of very scared people day after day for the rest of their lives. The question is this, Nardole: which one of us is stronger?” The answer? Nardole, of course, and he demonstrates his fortitude with his parting shot at the Doctor: “I’m going to name a town after you. A really rubbish one.” It’s okay to laugh and cry at the same time.

The Doctor and Bill Die…As promised, the Doctor does blow up a lot of silly tin men… and himself in the process. “No stars. I hoped there would be stars,” he says, as he closes his eyes for what he thinks is the last time. Then Bill comes clomping over and cries over him, her tears attracting the attention of Heather, the walking, talking puddle from the season premiere. The liquid-based alien works her magic, and Bill is suddenly herself again, while her cyber body collapses in a heap in the background. Of course, she’s not really herself…

And Rise Again“You’re like me now,” Heather informs her lover. “It’s just a different kind of living.” And while she offers Bill the chance to return to her normal life on Earth, the companion decides that she’d rather keep exploring the galaxy, this time independently of the TARDIS. (Her predecessor, Clara, enjoyed a similar fate, hitting the intergalactic highway with her new best friend, Ashildr, played by Maisie Williams.) “I’m never going to believe you’re really dead,” she tells the Doctor on her way out into the stars. “It’s a big universe. I hope I see you again.” We could — and will — say the same thing about you, Bill Potts. (Additional Whovian theorizing by Adam Lance Garcia.)